A Danish tap-water study tested larger visually selected objects against µFTIR chemical identification and blank-based detection thresholds, with additional smaller-particle analysis at selected sites.
Source details
Louise Feld, Vitor Hugo da Silva, Fionn Murphy, Nanna B. Hartmann, Jakob Strand. Water. 2021.
Findings
A Danish tap-water study tested larger visually selected objects against µFTIR chemical identification and blank-based detection thresholds, with additional smaller-particle analysis at selected sites.
Scroll horizontally for methods and limitations.
| Endpoint | Source-reported result | Locator |
|---|---|---|
| MP-like objects in Danish tap water | four of 124 selected objects | PDF pp. 7-8 §3.1; p. 11 conclusions |
| Visually classified objects | 44 MP-like objects per sample | PDF p. 6 §2.8; p. 7 §3.1 |
| Selected Danish tap-water filter fractions | three identified fragments | PDF p. 10 §3.2 and Table 1 |
| Small-particle Danish water analysis | 20 to 150 µm | PDF p. 10 §3.2 |
Methods and scope
Closed steel-filter tap sampling, 50 L/site. Microscopic screening for objects above 100 µm and µFTIR verification of representative subset. Additional hyperspectral imaging down to nominal 10 µm at three sites examined 10% of each final filter, representing 5 L. Five larger-particle blanks averaged 13.2 ± 9.4 MP-like objects, giving LoD 44/sample. Two small-particle blanks included one PET and rubber in one blank. Recovery experiments reported for fibers/beads/fragments.
What this source can support
Strong illustration of natural-fiber misidentification and the need to compare low counts with blanks. Supports source-specific counts, not a claim of zero plastic in all tap water.
All larger visual-object counts below blank-derived LoD. Only selected objects chemically validated. Smaller fraction assessed at only three locations and 10% of filter area. PET/rubber also found in a small-particle blank. Reported smaller-particle concentration estimates are extrapolated and not treated here as contamination-free tap-water concentrations. No nanoplastic assessment or health outcomes.
Related evidence
Reported values and source locations
| Reported value | Measurement basis | Conditions and size context | Original document location |
|---|---|---|---|
| four of 124 selected objects | Observed confirmed count/selected denominator; not full-sample concentration | µFTIR verification of representative larger MP-like objects from Danish tap-water samples >100 µm screened objects | PDF pp. 7-8 §3.1; p. 11 conclusions |
| 44 MP-like objects per sample | Limit of detection based on procedural blanks, not plastic regulatory limit | Blank-derived LoD for each 50 L sample; mean blank + 2 × 1.645 × blank SD >100 µm MP-like objects | PDF p. 6 §2.8; p. 7 §3.1 |
| three identified fragments | Observed count in analyzed portions; no full-filter conversion | µFTIR imaging of 10% filter area at three selected tap-water locations; blank PET/rubber also observed PP/PET 20-100 µm; ABS 100-150 µm | PDF p. 10 §3.2 and Table 1 |
| 20 to 150 µm | Reported identified-fragment size classes | PP/PET fragments 20-100 µm, ABS fragment 100-150 µm in selected filter areas 20-100 µm and 100-150 µm bins | PDF p. 10 §3.2 |
Source provenance
Primary PDF SHA-256: ebd2006452ff7ebf7f6ff46cf71a8a7dd9a0c6c4c5109d22bf307decdd1bd05d
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